Apache Cassandra 0.8 Documentation

What’s New in Cassandra 0.8

This document corresponds to an earlier product version. Make sure you are using the version that corresponds to your version.

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Cassandra 0.8 introduces the following major new features. For a complete description of all changes introduced in Cassandra 0.8, see the latest News and Changes files in the Apache Cassandra project repository.

  • Cassandra Query Language (CQL) - Cassandra 0.8 is the first release to include the Cassandra Query Language (CQL). As with SQL, clients built on CQL only need to know how to interpret query resultset objects. CQL is the future of Cassandra client API development. CQL drivers are hosted within the Apache Cassandra project. CQL syntax in based on SQL (Structured Query Language), the standard for relational database manipulation. Although CQL has many similarities to SQL, it does not change the underlying Cassandra data model. There is no support for JOINs, for example. See and Getting Started with CQL and CQL Command Reference for more information on using CQL in Cassandra 0.8.
  • Distributed Counters - A counter is a special kind of column used to store a number that incrementally counts the occurrences of a particular event or process. See the following topics for more information: the Developer Center Blog Post on Counters , About Counters and Creating a Counter Column Family.
  • Internode Encryption - The cassandra.yaml file now has options for configuring internode encryption.
  • Compaction Multi-Threading and Throttling - Two new cassandra.yaml options compaction_throughput_mb_per_sec and concurrent_compactors allow for tuning the impact of compaction on workload performance.
  • Improved Memory Configuration - By default, Cassandra limits memtable total memory usage to 1/3 of the Java heap size. This can be adjusted using the new memtable_total_space_in_mb option. The pre-0.8 per-column family memtable settings are still respected, but are deprecated and will be removed in a future release.
  • New Bulk Loader - A new bulk loader utility, sstableloader, takes data files in SSTable format and streams them into a live cluster. See the blog post on bulk data loading for more information.